Updating npm description to note webpack 4 support

Author: ScriptedAlchemy

package.json

@@ -5,7 +5,7 @@
   "contributors": [
     "Zack Jackson <zackary.l.jackson@gmail.com> (https://github.com/zackljackson)"
   ],
-  "description": "Extract CSS from chunks into stylesheets + HMR",
+  "description": "Extract CSS from chunks into stylesheets + HMR. Supports Webpack 4",
   "engines": {
     "node": ">= 6.9.0 <7.0.0 || >= 8.9.0"
   },